In many applications, quality assurance requirements dictate that machine settings must be verified periodically and that such verification is traceable to relevant national standards. For example laser power can be verified using a commercially available laser power meter which has been calibrated against a traceable standard by a suitably approved calibration laboratory. Likewise for many applications where there is physical modification of the surface, such as laser marking and additive layer manufacturing (ALM), scanning geometry can be verified against traceable linear measuring devices of various types. This can be performed either as an off-line check by measuring a special test pattern, or on-line by measuring actual product, or by a combination of both. However the verification of scan speed generally poses a problem. It cannot be directly verified by measurements on the product, although it does affect the attributes of the process. For example in ALM, scan speed is known to affect the strength and fatigue properties of the resulting product. Moreover laser processing systems do not generally provide a traceable means of verifying scan speed.